Srimad-Bhagavatam: Canto 7 - Chapter 1 - Verse 14

Sanskrit:

कर्मणाकृतिभिर्वाचा लिङ्गैर्वर्णाश्रमादिभि: ।न विदन्ति जना यं वै सोऽसाविति न वेति च ॥ १४ ॥

ITRANS:

karmaṇākṛtibhir vācāliṅgair varṇāśramādibhiḥna vidanti janā yaṁ vaiso ’sāv iti na veti ca

Translation:

Neither by that saintly person’s activities, by his bodily features, by his words nor by the symptoms of his varṇāśrama status could people understand whether he was the same person they had known.

Purport:

The inhabitants of that particular place on the bank of the Kāverī in the valley of the mountain known as Sahya were unable to understand whether that saint was the same man they had known. It is therefore said, vaiṣṇavera kriyā mudrā vijñe nā bhujhaya. A highly advanced Vaiṣṇava lives in such a way that no one can understand what he is or what he was. Nor should attempts be made to understand the past of a Vaiṣṇava. Without asking the saintly person about his previous life, Prahlāda Mahārāja immediately offered him respectful obeisances.